In her latest About.com article, Julia Houston looks at Sci-Fi and sex. Here's an excerpt from the piece dealing with Enterprise:

By contrast, and despite initial signs that sexuality would play a greater role on the show than it did in VOY, DS9, and TNG, Enterprise has given us little but "giggle and jiggle" sex meant to make us smirk at skin and laugh at sex for being so "ooky." Tucker gets pregnant, and the Klingons chortle so hard they almost pee on themselves. Archer and T'Pol get tied up together, and he ends up with her breasts in his face.